Discrete Cosine Transformation (DCT)-II, Haar, and Slant transform techniques are applied variously in signal processing. In particular, these signal transform techniques are used for image encoding processing or signal modulation.
The DCT, specifically, the DCT-II is used to process signals and images. The DCT is widely used for lossy compression because it has an energy compaction property in which most of signal energy components tend to be concentrated in a few low-frequency components. For example, JPEG image compression, MJPEG, MPEG, and DV video compression adopt the DCT. Two-dimensional DCT-II is applied to N×N blocks and its results are quantized and entropy-coded.
The Haar transform and the Slant transform are also useful in various signal processing fields.
Circuits for the DCT-II, the Haar transform, and the Slant transform are implemented as separate circuits or separate chips. However, when the transform circuits are separately provided, a device including the circuits increases in volume and its processing rate is retarded.
In this respect, what is needed is a method for realizing a unified circuit for the DCT-II, the Haar transform, and the Slant transform.